| dc.creator |
Ibarra, David |
|
| dc.creator |
Chávez Uribe, María Isabel |
|
| dc.creator |
Rencoret, Jorge |
|
| dc.creator |
Río Andrade, José Carlos del |
|
| dc.creator |
Gutiérrez Suárez, Ana |
|
| dc.creator |
Romero Sánchez, Javier |
|
| dc.creator |
Camarero, Susana |
|
| dc.creator |
Martínez Hernández, María Jesús |
|
| dc.creator |
Jiménez-Barbero, Jesús |
|
| dc.creator |
Martínez, Ángel T. |
|
| dc.date |
2008-03-25T15:52:05Z |
|
| dc.date |
2008-03-25T15:52:05Z |
|
| dc.date |
2007 |
|
| dc.date.accessioned |
2017-01-31T01:00:55Z |
|
| dc.date.available |
2017-01-31T01:00:55Z |
|
| dc.identifier |
Holzforschung 61(6): 634-646 (2007) |
|
| dc.identifier |
0018-3830 |
|
| dc.identifier |
http://hdl.handle.net/10261/3303 |
|
| dc.identifier |
http://dx.doi.org/10.1515/HF.2007.096 |
|
| dc.identifier |
1437-434X |
|
| dc.identifier.uri |
http://dspace.mediu.edu.my:8181/xmlui/handle/10261/3303 |
|
| dc.description |
Modification of eucalypt pulp residual lignin in a totally chlorine free (TCF) bleaching sequence including a laccase-mediator stage, in combination with previous oxygen delignification and subsequent peroxide bleaching, was investigated and compared with a chemical TCF sequence. The enzymatic treatment resulted in a strong oxidative modification, as shown by lignin unit 13C2,6-1H2,6 correlations in HSQC 2D-NMR spectra and presence of oxidized pyrolysis markers. The frequency of inter-unit linkages in residual lignin was also modified, as shown by different side-chain 13C-1H correlations. Moreover, H2,6 correlations with side-chain carbons in HMBC spectra revealed the presence of Cα keto and carboxyl groups in lignin from the oxygen-delignified and especially from the enzymatically-treated pulp, together with normal (Cα-hydroxylated) lignin units. Moreover, the results obtained showed that most of this oxidatively-altered lignin is removed under the alkaline conditions used in the peroxide stage. In this way, the pulp kappa number decreased, and the final residual lignin was more structurally-related to that found before the oxidative stages (although with lower content of resinol structures, and higher presence of aryl-aryl ether structures and carboxyl-bearing terminal units). However, the action of hydrogen peroxide is required to attain the high brightness, over 91% ISO, found in final pulp after the enzyme-containing TCF sequence. |
|
| dc.description |
Peer reviewed |
|
| dc.format |
466644 bytes |
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| dc.format |
application/pdf |
|
| dc.language |
eng |
|
| dc.rights |
openAccess |
|
| dc.subject |
2D-NMR |
|
| dc.subject |
Enzymes |
|
| dc.subject |
Eucalyptus globulus |
|
| dc.subject |
FTIR |
|
| dc.subject |
HMBC |
|
| dc.subject |
HSQC |
|
| dc.subject |
Laccase-mediator system |
|
| dc.subject |
Paper pulp |
|
| dc.subject |
Py-GC/MS |
|
| dc.subject |
TCF bleaching |
|
| dc.title |
Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
|
| dc.type |
Artículo |
|